Why is it so easy to polish off a sleeve of Oreos – while we struggle to eat a big salad? Because the amount of food we need to feel satisfied – also known as our satiety threshold – is higher for sugary treats than it is for other foods. That’s according to Dr. David Katz from the Yale Prevention Research Center. He says the sugar goes right through us, instead of lingering in our stomach. So to feel full on fewer calories, have protein before dessert. Protein takes longer to digest, so you’ll feel too full to eat the entire ice cream sundae.